With PrimeFaces, we can snap the dragged component to the inner or outer boundaries of another component (a component's DOM element).
In this recipe, we will discuss snapping and its options in detail. As an example, we will develop a big h:panelGroup component as a snap target and three other small h:panelGroup components as draggable components, with various snapping options.
Generally, the snapping behavior is activated by setting the attribute snap to true. The snapping behavior is configurable with two options—snapMode and snapTolerance. The first option, snapMode, determines which edges of snap elements the draggable component will snap to. The second option, snapTolerance, determines a distance in pixels the draggable component must be from the element when snapping is invoked.
<h:panelGroup id="snaptarget" layout="block" styleClass="ui-widget-content" style="height:150px;width:450px;"> <p class="ui-widget-header"...